Biodegradable PCL-PLGA-beta TCP scaffolds for bone tissue engineering

Statement of Purpose: Each year more than 2.2 million surgery is performed to treat the bone defects worldwide, which costs roughly $2.5 billion [1]. Typically, autogenous bone grafts are used to treat these defects. However, it results in donor site morbidity. Furthermore, allogeneic grafts are often not safe and very expensive. In this context, engineered synthetic scaffolds have shown to be a potential alternative to the bone grafts due to its unlimited supply. Therefore, porous scaffolds fabricated using biodegradable biomaterials to meet the required properties of the host tissue, are very promising to expedite the healing of bone defects. Importantly, in addition to provide an adequate surface for the osteoblast cells adhesion, proliferation, and differentiation as well as vascularization, these porous scaffolds should withstand the applied load. However, the engineered pores (created for the vascularization) may decrease the mechanical properties. Therefore, the focus of this study was to develop a biodegradable scaffold of polycaprolactone-poly(lactic-co-glycolic acid)-beta Tri-calcium phosphate (PCL-PLGA-βTCP) without pores and therefore, with improved mechanical properties. Importantly, faster degradation of PLGA than PCL led to the creation of in situ pores in the matrix of PCL, which can help in the neovascularization. Furthermore, the dissolution of βTCP is expected to help in the mineralization by supplying the Ca²⁺ 3-and PO₄ at the defect site, in vivo.